摘要:
A method for incorporating invisible APs for RSSI based indoor positioning is presented. An empirical estimate of the probability of invisible APs versus distance is computed. An estimated position of the receiver can be computed using any statistical estimator based on the probability. In one embodiment, an estimate of the probability is computed by combining the probability over a set of visible APs and the probability over a set of invisible APs with the probability of individual contribution. In one embodiment a dynamic procedure is used to update the invisible probability that is computed using an AP dictionary built on the fly as new APs are detected. Incorporating invisible APs for estimating user position from the RSSI measurements for indoor positioning provides a better positioning accuracy as compared to typical estimators which rely only on the visible APs.
摘要:
System and method for hybrid positioning using blended Wi-Fi and GNSS solution is presented, which provides an overall good positioning accuracy as compared to feed forward blending solution. Feeding back Wi-Fi and GNSS blended solutions to replace position states in GNSS enables blended solution to improve using past Wi-Fi information and also enables early correction of GPS drifts in urban canyons. Smart blending prevents early degradation of blended solution due to bad Wi-Fi information. Additionally, it gives good performance in open sky and mild urban canyons where GPS performance is generally quite good. Constrained blending enables good blending even with dependent or clustered Wi-Fi positions. It also keeps feedback loop stable by limiting changes to a blended solution.
摘要:
A transmitter used in a communication system includes a raised cosine filter for transmit pulse shaping. A receiver in the communication system, designed to receive and demodulate transmissions from the transmitter, includes a root-raised cosine filter for receive pulse shaping. The use of a raised cosine filter in the transmitter enables reduction of peak-to-average ratio (PAR) of the output of a power amplifier used in the transmitter, enabling the power amplifier to be implemented to have relatively higher power efficiency than otherwise. In an embodiment, the transmitter and receiver employ π/2-shift binary phase-shift keying (π/2 BPSK), and the raised cosine filter in the transmitter is implemented to have a roll-off factor of 0.5 and a total length of four symbol periods. In an embodiment, the root-raised cosine filter is implemented to have a roll-of factor of 0.2 and a length of four symbol periods.
摘要:
Methods and integrated circuits for performing receiver autonomous integrity monitoring (RAIM) in global navigation satellite system (GNSS) receivers are disclosed. In an embodiment, a first information comprising current position related information is accessed. A second information comprising predicted position related information is accessed based on previously received information. A solution is computed based on the first information and the second information and a presence of outlier information is determined in at least one of the first information and the second information based on the solution.
摘要:
The present invention provides a system for obviating interference effects in packet detection within a wireless communications network. A plurality of reference signals is provided—a first of which corresponds to desired packets, and the remainder of which correspond to undesired packets or interference. A plurality of cross-correlation constructs corresponds, respectively, to the plurality of reference signals. Each cross-correlation construct correlates an incoming signal to a plurality of repetitions of its respective reference signal. An analysis construct compares output from each cross-correlation construct with other cross-correlation construct outputs, and with a threshold value, to determine which incoming signal corresponds to desired packet data. Once this incoming signal is identified, packets from the signal may be reliably received.
摘要:
A system and method for determining a position of a mobile wireless device using wireless local area network access points (APs). In one embodiment, a mobile wireless device includes an AP positioning system configured to estimate a position of the device based on locations of APs disposed about the device. The AP positioning system is configured to: 1) access an AP database; and 2) provide, to the database, one or more medium access controller (MAC) addresses and an area of interest value. The AP positioning system is also configured to retrieve, from the database: 1) location information for each AP having a provided MAC address, or located within the area of interest; and 2) at least one of: signal parameters for the APs nearby the device, a geographic area within which each MAC address can be received, and an indication of a scan type to used for identifying APs.
摘要:
A method and an integrated circuit to improve sensitivity of decoding time of a GNSS receiver are disclosed. A plurality of estimates of states of an encoder for one or more instances of a time counter is maintained. A signal comprising a plurality of data bits corresponding to an instance of the time counter is detected and at least one augmented state for each estimate of states of the encoder is determined. A corresponding augmented state for successive instances of the time counter is predicted and an augmented branch metric for each of the at least one augmented state is computed. A path metric for the each estimate is updated based on the augmented branch metric for each of the at least one augmented state and a time counter value is determined based on the path metric for the each estimate.
摘要:
A transmitter used in a communication system includes a raised cosine filter for transmit pulse shaping. A receiver in the communication system, designed to receive and demodulate transmissions from the transmitter, includes a root-raised cosine filter for receive pulse shaping. The use of a raised cosine filter in the transmitter enables reduction of peak-to-average ratio (PAR) of the output of a power amplifier used in the transmitter, enabling the power amplifier to be implemented to have relatively higher power efficiency than otherwise. In an embodiment, the transmitter and receiver employ π/2-shift binary phase-shift keying (π/2 BPSK), and the raised cosine filter in the transmitter is implemented to have a roll-off factor of 0.5 and a total length of four symbol periods. In an embodiment, the root-raised cosine filter is implemented to have a roll-of factor of 0.2 and a length of four symbol periods.
摘要:
Signaling in a medical implant based system. A method includes transmitting bits modulated with a predefined sequence in a band of channels by a first medical transceiver. The method includes transmitting bits modulated with a first predefined sequence of a plurality of predefined sequences by a first medical transceiver. The first predefined sequence is detected by a second medical transceiver when the second medical transceiver enters into an active state. A predetermined action is preformed if the first predefined sequence is detected.
摘要:
Methods and integrated circuits for performing receiver autonomous integrity monitoring (RAIM) in global navigation satellite system (GNSS) receivers are disclosed. In an embodiment, a first information comprising current position related information is accessed. A second information comprising predicted position related information is accessed based on previously received information. A solution is computed based on the first information and the second information and a presence of outlier information is determined in at least one of the first information and the second information based on the solution.